Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A method and apparatus for transferring data. First data is transferred
in a first direction on a surface of a selected magnetic disk in a
plurality of magnetic disks using a first actuator assembly. Second data
is transferred in a second direction on the surface of the selected
magnetic disk in the plurality of magnetic disks using a second actuator
assembly, while the first data is being transferred in the first
direction by the first actuator assembly.

Claims:

1. A disk drive comprising: a plurality of magnetic disks; a first
actuator assembly configured to transfer first data with the plurality of
magnetic disks; and a second actuator assembly configured to transfer
second data with the plurality of magnetic disks, wherein the first
actuator assembly transfers the first data in a first direction on a
surface of a selected magnetic disk in the plurality of magnetic disks
while the second actuator assembly transfers the second data in a second
direction on the surface of the selected magnetic disk in the plurality
of magnetic disks.

2. The disk drive of claim 1, wherein the first actuator assembly
transfers the first data in the first direction for a first magnetic disk
in the plurality of magnetic disks while the second actuator assembly
transfers the second data in the second direction for a second magnetic
disk in the plurality of magnetic disks.

3. The disk drive of claim 1, wherein the first actuator assembly moves a
first number of arms about a first axis and the second actuator assembly
moves a second number of arms about a second axis.

4. The disk drive of claim 1 further comprising: a first preamplifier
connected to the first actuator assembly; and a second preamplifier
connected to the second actuator assembly.

5. The disk drive of claim 1, wherein the first actuator assembly
comprises a first number of arms and a first number of read and write
units and the second actuator assembly comprises a second number of arms
and a second number of read and write units.

6. The disk drive of claim 1 further comprising: a read channel connected
to the first actuator assembly and the second actuator assembly.

7. The disk drive of claim 4 further comprising: a read channel connected
to the first preamplifier and the second preamplifier.

8. The disk drive of claim 6 further comprising: a disk formatter
connected to the read channel.

9. The disk drive of claim 1 further comprising: a positioning system
configured to control a position of the first actuator assembly and a
position of the second actuator assembly relative to the plurality of
magnetic disks.

10. The disk drive of claim 1 further comprising: a hard disk controller
configured to control transfer of the first data in the first direction
using the first actuator assembly and transfer of the second data in the
second direction using the second actuator assembly.

11. The disk drive of claim 10, wherein the hard disk controller
comprises: a read channel; a positioning system connected to the read
channel, the first actuator assembly, and the second actuator assembly,
wherein the positioning system is configured to control the first
actuator assembly and the second actuator assembly; a disk formatter
connected to the read channel; a memory unit connected to the disk
formatter; and a host interface connected to the memory unit.

13. An apparatus comprising: a number of circuits configured to control
transfer of first data in a first direction on a surface of a selected
magnetic disk in a plurality of magnetic disks using a first actuator
assembly and transfer of second data in a second direction on the surface
of the selected magnetic disk in the plurality of magnetic disks using a
second actuator assembly.

14. The apparatus of claim 13, wherein the number of circuits is embodied
on an integrated circuit.

15. The apparatus of claim 14, wherein the integrated circuit is a hard
disk controller.

16. The apparatus of claim 14, wherein the integrated circuit is for a
disk formatter.

17. A method for transferring data, the method comprising: transferring
first data in a first direction on a surface of a selected magnetic disk
in a plurality of magnetic disks using a first actuator assembly; and
transferring second data in a second direction on the surface of the
selected magnetic disk in the plurality of magnetic disks using a second
actuator assembly, while the first data is being transferred in the first
direction by the first actuator assembly.

18. The method of claim 17 further comprising: identifying the first data
for transfer in the first direction; identifying the second data for
transfer in the second direction; identifying first locations on the
plurality of magnetic disks for transferring the first data in the first
direction; identifying second locations on the plurality of magnetic
disks for transferring the second data in the second direction.

19. The method of claim 18 further comprising: moving a first read and
write unit in the first actuator assembly to the first locations to
transfer the first data in the first direction; and moving a second read
and write unit in the second actuator assembly to the second locations to
transfer the second data in the second direction.

20. The method of claim 17, wherein the first actuator assembly comprises
a first number of arms and a first number of read and write units and the
second actuator assembly comprises a second number of arms and a second
number of read and write units.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present disclosure is directed generally toward disk drives
and, in particular, to data access systems in hard disk drives. Still
more particularly, the present disclosure is related to a method and
apparatus for increasing the rate at which data on magnetic disks is
accessed.

[0003] 2. Description of the Related Art

[0004] A disk drive is a device that stores data on magnetic media. In
particular, a disk drive stores digital data on magnetic disks. These
magnetic disks take the form of rigid platters that rotate on a spindle
within an enclosure. Each disk is divided into magnetic regions. These
regions may take the form of tracks on the disks. Data is read and
written on these magnetic disks using read and write head assemblies that
are moved over different locations on the magnetic disks.

[0005] Many applications require the transfer of large amounts of data to
and from a hard disk drive. For example, the recording and editing of
video data involves the transfer of larger amounts of data, as compared
to word processing documents. Many applications also require large
numbers of disk accesses to hard disk drives. A database application is
an example of an application that may require large numbers of disk
accesses.

[0006] These disks include magnetic media on which data may be stored.
Users of applications typically want to perform different tasks and
functions as quickly as possible. As a result, the speed at which data
can be accessed on a disk drive is increasing. As the need for increased
performance in disk drives continues to grow, currently used disk drives
may not provide a desired amount of access. Therefore, it would be
advantageous to have a method and apparatus that takes into account one
or more of the issues discussed above, as well as other possible issues.

SUMMARY OF THE INVENTION

[0007] In one illustrative embodiment, a disk drive comprises a plurality
of magnetic disks; a first actuator assembly, and a second actuator
assembly. The first actuator assembly is configured to transfer first
data with the plurality of magnetic disks. The second actuator assembly
is configured to transfer second data with the plurality of magnetic
disks. The first actuator assembly transfers the first data in a first
direction on a surface of a selected magnetic disk in the plurality of
magnetic disks, while the second actuator assembly transfers the second
data in a second direction on the surface of the selected magnetic disk
in the plurality of magnetic disks.

[0008] In another illustrative embodiment, an apparatus comprises a number
of circuits configured to control transfer of first data in a first
direction on a surface of a selected magnetic disk in a plurality of
magnetic disks using a first actuator assembly and transfer of second
data in a second direction on the surface of the selected magnetic disk
in the plurality of magnetic disks using a second actuator assembly.

[0009] In yet another illustrative embodiment, a method is provided for
transferring data. First data is transferred in a first direction on a
surface of a selected magnetic disk in a plurality of magnetic disks
using a first actuator assembly. Second data is transferred in a second
direction on the surface of the selected magnetic disk in the plurality
of magnetic disks using a second actuator assembly, while the first data
is being transferred in the first direction by the first actuator
assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The novel features believed characteristic of the invention are set
forth in the appended claims. The invention itself however, as well as a
preferred mode of use, further objects and advantages thereof, will best
be understood by reference to the following detailed description of an
illustrative embodiment when read in conjunction with the accompanying
drawings, wherein:

[0011] FIG. 1 is a block diagram of a disk drive in accordance with an
illustrative embodiment;

[0012]FIG. 2 is an illustration of actuator assemblies and magnetic disks
in a disk drive in accordance with an illustrative embodiment; and

[0013]FIG. 3 is an illustration of a flowchart of a process for
transferring data to and from magnetic disks in accordance with an
illustrative embodiment.

DETAILED DESCRIPTION

[0014] The different embodiments take into account a number of
considerations. For example, the different illustrative embodiments
recognize and take into account that with currently available disk
drives, a single actuator system is typically present. The use of a
single actuator system is a factor in the amount of data that can be
accessed on magnetic disks in a disk drive.

[0015] The different illustrative embodiments recognize and take into
account that one manner in which the speed at which data may be accessed
on a magnetic disk in a disk drive may involve the use of more than one
actuator assembly in the disk drive. For example, the different
illustrative embodiments recognize and take into account that two
actuator assemblies may be used to position read and write heads over the
magnetic disks in a disk drive. The different illustrative embodiments
recognize and take into account that the actuator assemblies may be used
to increase the speed at which data is read. It is desirable to have the
fastest rate of data access possible.

[0016] The different illustrative embodiments recognize and take into
account that, with the use of two actuator assemblies, parallel reads and
parallel writes can be used. These parallel reads and writes mean that
data can be transferred more quickly. For example, in a parallel read,
the different illustrative embodiments recognize and take into account
that one actuator assembly reads data from one portion of a disk drive
while another actuator assembly reads data from another portion of the
disk drive. In a similar fashion, if data is written to the disk drive,
part of the data may be written to one portion of the disk drive using
one actuator assembly while another portion of the data may be written to
a different portion of the disk drive using the second actuator assembly.
In this manner, reads and writes may be performed more quickly using two
actuator assemblies rather than a single actuator assembly.

[0017] The different illustrative embodiments recognize and take into
account that with parallel reading and parallel writing of data, the
complexity of the hard disk drive increases. For example, the different
illustrative embodiments recognize and take into account that two read
controllers and two write controllers are needed to perform reading and
writing data in parallel.

[0018] Further, the different illustrative embodiments recognize and take
into account that, in addition to requiring more logic and circuits, the
complexity of controlling the reads and writes also increases. For
example, if data is received to be written to the magnetic disk, firmware
or other logic is needed to divide the data that is being received and
send the data to the different actuator assemblies in a manner that
results in a correct writing of the data to the disk. A similar type of
logic or firmware is also needed to read data from the disk and send the
data for use.

[0019] The different illustrative embodiments also recognize and take into
account that these increases in the complexity of the disk drive require
additional components or circuits. As a result, the amount of real estate
needed on an integrated circuit increases when parallel reads and writes
are provided through multiple actuator assemblies. Additionally, this
complexity also may result in undesired increases in the cost to design
and manufacture disk drives.

[0020] Thus, the different illustrative embodiments provide a method and
apparatus for increasing access to magnetic disks in a disk drive. In one
illustrative embodiment, an apparatus comprises a plurality of magnetic
disks, a first actuator assembly, and a second actuator assembly. The
first actuator assembly and the second actuator assembly are configured
to transfer data with the plurality of magnetic disks. The first actuator
assembly is configured to transfer the data in a first direction in the
plurality of magnetic disks, while the second actuator assembly transfers
the data in a second direction in the plurality of magnetic disks.

[0021] With reference now to the figures and, in particular, with
reference to FIG. 1, a block diagram of a disk drive is depicted in
accordance with an illustrative embodiment. Disk drive 100 may be used
with various types of data processing systems. For example, disk drive
100 may be used to store data in a desk computer, a server computer, a
laptop computer, a digital camera, a video camera, or some other suitable
type of data processing system. Further, disk drive 100 may be
implemented as an internal component within the data processing system or
may be attached to the data processing system externally. In this
example, disk drive 100 comprises disk assembly 102 and printed circuit
board assembly 104.

[0023] As used herein, when a first component is connected to a second
component, the first component may be connected to the second component
without any additional components. The first component may also be
connected to the second component by one or more other components. For
example, one electronic device may be connected to a second electronic
device without any additional electronic devices between the first
electronic device and the second electronic device. In some cases,
another electronic device may be present between the two electronic
devices connected to each other.

[0025] Actuator assemblies 108 include first actuator assembly 124 and
second actuator assembly 126. First actuator assembly 124 has first
number of arms 134 and first number of read and write units 136. Second
actuator assembly 126 has second number of arms 138 and second number of
read and write units 140. As used herein, a number, when used with
reference to items, means one or more items. For example, "first number
of arms 134" is one or more arms.

[0026] In these illustrative examples, one or more of first number of read
and write units 136 may be connected to, or otherwise associated with, an
arm in first number of arms 134. In a similar fashion, one or more of
second number of read and write units 140 may be connected to an arm
within second number of arms 138.

[0027] Printed circuit board assembly 104 comprises hard disk controller
120 and host connector 122. In these illustrative examples, hard disk
controller 120 is connected to host connector 122. Hard disk controller
120 controls the reading and writing of data 146 with respect to
plurality of magnetic disks 106. Host connector 122 is configured for
connection to other components in a data processing system. For example,
host connector 122 may be connected to a bus or other connector in a data
processing system. Host connector 122 may be, for example, without
limitation, a fire wire connection, a universal serial bus connection, a
peripheral inter-connect connection, or some other suitable type of
connection.

[0028] As illustrated, hard disk controller 120 comprises positioning
system 112, read channel 118, disk formatter 158, memory unit 160, and
host interface 161. Positioning system 112 includes first servo 128 and
second servo 130. A servo is a device configured to control the position
of an actuator assembly. In these examples, the position is relative to a
location on surfaces 132 on plurality of magnetic disks 106.

[0029] As depicted, first servo 128 is connected to first actuator
assembly 124, and second servo 130 is connected to second actuator
assembly 126. First servo 128 controls the movement of first actuator
assembly 124 over surfaces 132 of plurality of magnetic disks 106 to move
first actuator assembly 124 to a desired position over surfaces 132. In a
similar fashion, second servo 130 controls the movement of second
actuator assembly 126 over surfaces 132 of plurality of magnetic disks
106 to move second actuator assembly 126 to a desired position over
surfaces 132.

[0030] More specifically, first servo 128 moves first number of arms 134
in a manner to position first number of read and write units 136 over
surfaces 132 of plurality of magnetic disks 106. In a similar fashion,
second servo 130 moves second number of arms 138 in a manner to position
second number of read and write units 140 over surfaces 132 of plurality
of magnetic disks 106.

[0031] In these depicted examples, first actuator assembly 124 and second
actuator assembly 126 are configured to transfer data 146 with plurality
of magnetic disks 106. For example, first servo 128 and second servo 130
may control first actuator assembly 124 and second actuator assembly 126
to transfer data 146 with selected magnetic disk 125 of plurality of
magnetic disks 106.

[0032] In particular, selected magnetic disk 125 has first side 127 and
second side 129. Selected magnetic disk 125 has first surface 131 on
first side 127 and second surface 133 on second side 129. First actuator
assembly 124 and second actuator assembly 126 are configured to transfer
data 146 on first surface 131 and/or second surface 133 of selected
magnetic disk 125. In these depicted examples, when data is transferred
on a surface, the data may be written onto the surface or read from the
surface.

[0033] As one illustrative example, first actuator assembly 124 is
configured to transfer first data 152 in data 146 in first direction 148
on first surface 131 of selected magnetic disk 125, and second actuator
assembly 126 is configured to transfer second data 154 in data 146 in
second direction 150 on second surface 133 of selected magnetic disk 125.
In these illustrative examples, first actuator assembly 124 transfers
first data 152 in first direction 148 on first surface 131, while second
actuator assembly 126 transfers second data 154 in second direction 150
on second surface 133.

[0034] In this illustrative example, the transfer of first data 152 in
first direction 148 and the transfer of second data 154 in second
direction 150 may be a read or a write of data. For example, if the
transfer of first data 152 in first direction 148 is a read of first data
152 from selected magnetic disk 125, then the transfer of second data 154
in second direction 150 is a write of second data 154 to selected
magnetic disk 125. When first direction 148 is a write of data to
selected magnetic disk 125, second direction 150 is a read of data from
selected magnetic disk 125.

[0035] As a result, data 146 may be read and written at the same time. In
other words, simultaneous reading and writing of data 146 is provided in
the different illustrative embodiments. Further, data 146 may be read and
written with respect to disk drive 100 on the same magnetic disk within
plurality of magnetic disks 106 or on different magnetic disks when in
plurality of magnetic disks 106.

[0036] In these illustrative examples, first actuator assembly 124 and
second actuator assembly 126 may transfer data 146 with selected magnetic
disk 125 on first surface 131 of selected magnetic disk 125. However, in
other illustrative examples, first actuator assembly 124 and second
actuator assembly 126 may be configured to transfer data 146 with both
first surface 131 and second surface 133 of selected magnetic disk 125 at
the same time.

[0037] For example, first actuator assembly 124 may transfer first data
152 in first direction 148 on first surface 131 of selected magnetic disk
125, while second actuator assembly 126 transfers second data 154 in
second direction 150 on second surface 133 of selected magnetic disk 125.
In some illustrative examples, first actuator assembly 124 and second
actuator assembly 126 may be configured to transfer data 146 on the
surfaces of two different magnetic disks in plurality of magnetic disks
106.

[0038] In these illustrative examples, the transfer of first data 152 in
first direction 148 and the transfer of second data 154 in second
direction 150 is provided through the use of separate preamplifiers,
servos, and actuator assemblies. Through these and other suitable
components, first actuator assembly 124 and second actuator assembly 126
may be in different positions to perform a read and write at the same
time.

[0039] As illustrated, read channel 118 provides an interface between
printed board circuit assembly 104 and disk assembly 102 and is
configured to support transfers of data 146 in first direction 148 and
second direction 150. In these illustrative examples, the transfers of
data 146 may take the form of read and write operations. As depicted,
read channel 118 has plurality of channels 156. Plurality of channels 156
is configured such that data 146 may be written in first direction 148
and second direction 150 through plurality of channels 156 at the same
time. For example, a portion of plurality of channels 156 may be
configured for performing read operations, while another portion of
plurality of channels 156 may be configured for performing write
operations.

[0040] Read channel 118 is connected to disk formatter 158. Disk formatter
158 is configured to control reading and writing of data. For example,
disk formatter 158 is configured to transfer data 146 in first direction
148 and second direction 150 at the same time. Further, disk formatter
158 is connected to positioning system 112. More specifically, disk
formatter 158 is connected to first servo 128 and second servo 130.

[0041] Additionally, read channel 118 is connected to first preamplifier
142 and second preamplifier 144. First preamplifier 142 and second
preamplifier 144 are configured to amplify read signals received in
plurality of channels 156 from first actuator assembly 124 and second
actuator assembly 126, respectively, and amplify write signals sent
through plurality of channels 156 to first actuator assembly 124 and
second actuator assembly 126.

[0042] Host interface 161 is connected to host connector 122 and comprises
a number of logic units configured to communicate with a host through
host connector 122. Further, host interface 161 is also connected to
memory unit 160. In this illustrative example, memory unit 160 may be
implemented using, for example, static random access memory (SRAM) and/or
dynamic random access memory (DRAM). Memory unit 160 functions as a
buffer for data transfer between a host and disk drive 100.

[0043] In one illustrative example, signals for performing write
operations are received through host connector 122. In other words, the
signals represent commands to perform a write operation and/or data that
is to be written. These signals may be sent from host connector 122 to
hard disk controller 120 through host interface 161. The signals are then
sent to memory unit 160. In these depicted examples, memory unit 160
stores data to be written to plurality of magnetic disks 106. Memory unit
160 functions as a buffer for the data until disk formatter 158 processes
the signals and data.

[0044] When the signals are sent from memory unit 160 to disk formatter
158, disk formatter 158 processes the signals for performing the write
operation and sends commands to one of first servo 128 and second servo
130. In this example, disk formatter 158 sends commands to first servo
128. First servo 128 controls the position of first actuator assembly 124
to move first actuator assembly 124 to a desired position for performing
the write operation. Disk formatter 158 also sends write signals through
plurality of channels 156 in read channel 118. These write signals are
then sent through first preamplifier 142 to first actuator assembly 124
to write the data to a magnetic disk in plurality of magnetic disks 106.

[0045] In this illustrative example, signals for performing a read
operation through host connector 122 may be received in hard disk
controller 120 through host interface 161 at a substantially same time as
when the signals for performing the write operation are received. These
signals are then sent to memory unit 160 and stored until disk formatter
158 can process the signals. When the signals are sent from memory unit
160 to disk formatter 158, disk formatter 158 processes the signals for
performing the read operation and sends commands to second servo 130 in
this illustrative example. Second servo 130 controls the position of
second actuator assembly 126 to move second actuator assembly 126 to a
desired position for performing the read operation. The position for
performing the read operation cannot be the same position for performing
the write operation if the two operations are to be performed on a same
surface of a same magnetic disk in plurality of magnetic disks 106.

[0046] Additionally, disk formatter 158 sends read signals through
plurality of channels 156 in read channel 118. These read signals are
sent through second preamplifier 144 to second actuator assembly 126 to
read data from a magnetic disk in plurality of magnetic disks 106. Data
that is read by second actuator assembly 126 is sent to read channel 118
through second preamplifier 144. Second preamplifier 144 is configured to
read the analog signals from the magnetic disk and amplify the signals
before passing the signals to read channel 118. In these illustrative
examples, the data that is read is then be sent through disk formatter
158, memory unit 160, host interface 161, and host connector 122 to the
host that initiated the read operation.

[0047] As read channel 118 performs read and write operations, read
channel 118 uses servo information written on plurality of magnetic disks
106 to monitor the position of first number of read and write units 136
and second number of read and write units 140 during read and write
operations. The servo information may also be referred to as servo data
or servo codes. In particular, read channel 118 reads the servo
information on plurality of magnetic disks 106 during read and write
operations. The servo information allows first actuator assembly 124 and
second actuator assembly 126 to know the positions of first number of
read and write units 136 and second number of read and write units 140
relative to plurality of magnetic disks 106.

[0048] This servo information is sent to first servo 128 and/or second
servo 130. First servo 128 and second servo 130 use the servo information
to determine whether changes to the speed of rotation of spindle 110 need
to be made to adjust the position of first number of read and write units
136 and/or second number of read and write units 140. First servo 128
and/or second servo 130 send signals to combo 116 to control the level of
current sent to spindle motor 114. Controlling the level of current
causes spindle 110 to rotate at a desired speed of rotation. In this
manner, a feedback loop is provided through combo 116, first servo 128,
and second servo 130.

[0049] In different illustrative examples, one or more components within
disk drive 100 may be implemented using circuits 162. Circuits 162 may be
formed using integrated circuit technology. For example, at least one of
hard disk controller 120, read channel 118, host connector 122, first
servo 128, second servo 130, first preamplifier 142, second preamplifier
144, disk formatter 158, memory unit 160, and other components may be
implemented using circuits 162 in the form of integrated circuits 164.
Further, these different components may be located on the same integrated
circuit or different integrated circuits within integrated circuits 164.
An integrated circuit also may be referred to as a chip or microchip.

[0050] The illustration of disk drive 100 in FIG. 1 is not meant to imply
physical or architectural limitations to the manner in which different
illustrative embodiments may be implemented. Other components in addition
to and/or in place of the ones illustrated may be used. Some components
may be unnecessary in some illustrative embodiments. Also, the blocks are
presented to illustrate some functional components. One or more of these
blocks may be combined and/or divided into different blocks when
implemented in different illustrative embodiments.

[0051] For example, in some illustrative embodiments, read channel 118 may
be a separate component from hard disk controller 120. For example, read
channel 118 may be a component external to hard disk controller 120 and
connected to hard disk controller 120 on printed circuit board assembly
104. Further, in some illustrative embodiments, the different connections
between different components may be made through optical connections
rather than electrical connections, depending on the particular
implementation. Further, in some illustrative examples, hardware modules
may be present to implement various functions rather than using program
code, depending on the particular implementation.

[0052] With reference now to FIG. 2, an illustration of actuator
assemblies and magnetic disks in a disk drive is depicted in accordance
with an illustrative embodiment. In this illustration, plurality of
magnetic disks 202 is an example of one implementation for plurality of
magnetic disks 106 in FIG. 1. Plurality of magnetic disks 202 comprises
magnetic disk 204, magnetic disk 206, and magnetic disk 208. Actuator
assemblies 210 are an example of one implementation for actuator
assemblies 108 in FIG. 1.

[0054] Further, third actuator assembly 213 has arm 232, arm 234, and arm
236. As depicted arm 232, arm 234, and arm 236 may move about axis 237.
Fourth actuator assembly 214 has arm 238 and two other arms (not shown in
this view). Arm 238 and the other two arms may move about axis 239. Each
arm in an actuator assembly may rotate independently of another arm in
the same actuator assembly about the axis corresponding to the actuator
assembly. For example, for third actuator assembly 213, arm 236 may
rotate a first number of degrees, while arm 234 rotates a second number
of degrees.

[0056] Each actuator assembly may transfer data in different directions
from other actuator assemblies. For example, first actuator assembly 211
may transfer data in a first direction, while second actuator assembly
212 transfers data in a second direction. Further, third actuator
assembly 213 may transfer data in a direction different from fourth
actuator assembly 214.

[0058] In the different illustrative examples, first actuator assembly 211
and second actuator assembly 212 are configured to transfer data on the
same surface of a magnetic disk. Third actuator assembly 213 and fourth
actuator assembly 214 are also configured to transfer data on the same
surface of a magnetic disk. In particular, first actuator assembly 211
and second actuator assembly 212 are configured to transfer data on a
first surface of a magnetic disk opposite to a second surface of the
magnetic disk on which third actuator assembly 213 and fourth actuator
assembly 213 are configured to transfer data.

[0059] For example, arm 216 of first actuator assembly 211 and arm 222 of
second actuator assembly 212 may both read from and write to,
respectively, the upper surface of magnetic disk 204. Arm 218 and arm 224
may both read from and write to, respectively, the upper surface of
magnetic disk 206. Arm 220 and arm 226 may both read from and write to,
respectively, the upper surface of magnetic disk 208. Similarly, arm 232
and arm 238 may both read from and write to, respectively, the lower
surface of magnetic disk 204. Arm 234 and an arm for fourth actuator
assembly 214 may both read from and write to, respectively, the lower
surface of magnetic disk 206. Arm 236 and another arm for fourth actuator
assembly 214 may both read from and write to, respectively, the lower
surface of magnetic disk 208.

[0060] As one illustrative example, read and write unit 240 on arm 216 may
read from the upper surface of magnetic disk 204 while the read and write
unit on arm 238 may write to the lower surface of magnetic disk 204. As
another example, read and write unit 242 on arm 218 may read from the
upper surface of magnetic disk 206, while the read and write unit on arm
234 may read from the lower surface of magnetic disk 206. In some cases,
the read and write unit on arm 236 may read from the lower surface of
magnetic disk 208, while the read and write unit on an arm for fourth
actuator assembly 214 writes to the lower surface of magnetic disk 208.

[0061] In this illustrative example, any number of read and write units
for first actuator assembly 211, second actuator assembly 212, third
actuator assembly 213, and fourth actuator assembly 214 may perform read
or write operations on plurality of magnetic disks 202. In this manner,
read and write operations may be performed on the same surface of the
same magnetic disk, on two different surfaces of the same magnetic disk,
or on two different magnetic disks in plurality of magnetic disks 202.
Further, read and write operations may be performed at substantially the
same time or at different times.

[0062] For example, the reading and writing of data on magnetic disk 204
by read and write unit 240 on arm 216 and read and write unit 234 on arm
246 may be started at substantially the same time. This type of start
indicates that the read and write operations are performed synchronously
and have a synchronous start. When the reading and writing of data on
magnetic disk 204 stops at substantially the same time, the read and
write operations have a synchronous stop. In other illustrative examples,
the read and write operations may be performed at different times with
different start times and/or stop times. In other words, these types of
read and write operations are performed asynchronously.

[0063] With reference now to FIG. 3, an illustration of a flowchart of a
process for transferring data to and from magnetic disks is depicted in
accordance with an illustrative embodiment. The process described in FIG.
3 may be implemented using hard disk controller 120 in FIG. 1. In
particular, this process is implemented using hard disk controller 120 to
transfer data 146 to and from plurality of magnetic disks 106 in FIG. 1.

[0064] The process begins by identifying first data for transfer in a
first direction (step 300). Second data for transfer in a second
direction is identified (step 302). First locations on a plurality of
magnetic disks for transferring the first data in the first direction are
identified (step 304). Second locations on the plurality of magnetic
disks for transferring the second data in the second direction are
identified (step 306).

[0065] The process then transfers the first data in the first direction on
a surface of a selected magnetic disk in the plurality of magnetic disks
using a first actuator assembly (step 308). Step 308 may occur with the
process controlling the first actuator assembly to move a first read and
write unit in the first actuator assembly to the first locations to
transfer the first data in the first direction.

[0066] The process then transfers the second data in the second direction
on the surface of the selected magnetic disk in the plurality of magnetic
disks using a second actuator assembly, while the first data is being
transferred in the first direction (step 310), with the process
terminating thereafter. Step 310 may be performed by the hard disk
controller causing a second actuator assembly to move a second read and
write unit in the second actuator assembly to the second locations to
transfer the second data in the second direction. In this manner, the
transfer of first data in the first direction and the transfer of second
data in the second direction may be performed simultaneously.

[0067] Thus, the different illustrative embodiments provide a method and
apparatus for transferring data with magnetic disks in a hard disk drive.
The disk drive comprises a plurality of magnetic disks; a first actuator
assembly, and a second actuator assembly. The first actuator assembly is
configured to transfer first data with the plurality of magnetic disks.
The second actuator assembly is configured to transfer second data with
the plurality of magnetic disks. The first actuator assembly transfers
the first data in a first direction on a surface of a selected magnetic
disk in the plurality of magnetic disks, while the second actuator
assembly transfers the second data in a second direction on the surface
of the selected magnetic disk in the plurality of magnetic disks.

[0068] In this manner, the transfer of data may be increased using one or
more of the different illustrative embodiments. The increase in the
transfer of data may occur while reducing the increase in the complexity
of circuits, software, or other components in the hard disk drive.

[0069] The description of the illustrative embodiments has been presented
for purposes of illustration and description, but is not intended to be
exhaustive or limited to the invention in the form disclosed. Many
modifications and variations will be apparent to those of ordinary skill
in the art. The illustrative embodiment was chosen and described in order
to best explain the principles of the invention and the practical
application to enable others of ordinary skill in the art to understand
the invention for various embodiments with various modifications as are
suited to the particular use contemplated.

Patent applications by LSI Corporation

Patent applications in class GENERAL RECORDING OR REPRODUCING

Patent applications in all subclasses GENERAL RECORDING OR REPRODUCING